Such an occlusion device is in principle to at least some extent partly known from medical technology. For example, in WO2005020822 of the same applicant as the present application, which is incorporated by reference herein for all purposes, an occlusion device for the treatment of septum defects is disclosed, which comprises of a network or braid of thin wires or threads and is given a suitable design by means of a reshaping and heat treatment process. The known occlusion device has a distal retention region, which is distinctively particularly flat, a proximal retention region, and a cylindrical web between the proximal and the distal retention region. On the proximal retention region, the ends of the wires forming the network meet in a hub. It is provided here for the two retention regions of the known occlusion device to fit tightly in a septal wall on both sides of a shunt to be occluded by means of a usually intravascular surgical intervention, while the web runs through the shunt. The occlusion device is suited in order to permanently occlude an opening having a dynamic blood flow, and to this end has a special construction and is not suitable for atrial appendage occlusions.
Similar devices are described in the German patent application No. 102005053957.2 of 5 Nov. 2005 and their identical applications PCT/EP2005/012130 of 5 Nov. 2005 and the U.S. application Ser. No. 11/271,751 of 19 Dec. 2005, of the same applicant as the present application, which all are incorporated by reference herein for all purposes.
If a patient is suffering from “atrial fibrillation” of the heart, particular embolism-related problems may appear. Here, there is frequent excitation of the atria of the heart, which does not lead to any contraction of the atria. The result of this loss of contraction of the atria of the heart is that effective agitation and mixing of the blood fails to occur and thrombi can be formed in the atrium. A considerable risk in case of formation of atrial thrombi as result of atrial fibrillation consists in the fact that such thrombi can be carried along with the bloodstream and reach the arterial circulation. The results of this embolization are in particular strokes, which occur to approximately 5% per year in patients with atrial fibrillation if anticoagulation of the blood is not carried out by chronic treatment with dicoumarol. However, bringing about the anticoagulation of the blood with dicoumarol, is likewise not without risk. Side effects of the treatment with dicoumarol are increased hemorrhages, so that contraindications exist for this treatment in about 20% of patients with atrial fibrillation and patients thus accept the risk of a stroke based on hemorrhage/stroke risk assessment.
Thrombi in the atrium of the heart develop in a vast majority in the “atrial appendages”. The atrial appendages are protrusions on the atria of the human heart, hanging over from each atrium as projections like a small ear, more marked on the left, each with a cavity of its own. The right atrial appendage lies beside the ascending aorta, and the left atrial appendage beside the large pulmonary artery. Here, the left atrial appendage in patients with atrial fibrillation is the frequent site of formation for blood clots, which can induce stroke when carried along with the blood flow.
On account of the risks and problems mentioned in connection with the formation of atrial thrombi above described, the present invention is based on the object of specifying an improved occlusion device by which the atrial appendage of the left atrium can be occluded in order to considerably reduce thrombus formation with the risk of a stroke. In particular, an occlusion device is to be specified with which the risk of stroke can be reduced even in those patients in which anticoagulation with dicoumarols is contraindicated on account of hypocoagulability. Likewise, the occlusion device provided is securely anchorable in the atrial appendage, without detaching itself, which is particular of advantage when anticoagulation agents and/or blood thinner agents have been administered to the patient. Patients suffering from atrial fibrillation are usually prescribed a powerful blood thinner, such as Coumadin.
According to the prior art, various solutions exist which essentially combine partial networks with rod-like structural elements, in some cases lasered constructions are also employed here in this combination, of the type such as disclosed in: EP 1417933A1; U.S. Pat. No. 7,169,164B2; US 2005/0234543A1; U.S. Pat. No. 6,689,150B1; U.S. Pat. No. 6,152,144 relate to this.
These devices, inter alia, have the disadvantage that relatively large insertion locks of up to 14 F internal diameter are needed for the implantation.
Further devices, such as of Amplatz PCT/US 2005/010551, according to the PLAATO method (PLAATO=Percutaneus Left Atrial Appendage Transcatheter) and Watchman occluder do not cope with the correct specified positioning. In the PLAATO system, the danger of perforation with the pericardium exists, moreover, PLAATO was likewise implanted using a 14F lock.
A further application of the same applicant as the present application, relates to a single hub atrial appendage occluder using a fixing agent for the formation of a force-fit connection between the network of an occlusion body and the atrial appendage wall, PCT/EP 2006/005292 of 06.02.2006. Here, the fixing agent is designed, after application, to harden so giving a flexible insoluble product, in particular, in a controlled manner, in order thus to produce a permanent and fixed anchoring between the network of the occlusion body and the atrial appendage wall. According to the application, it is provided for the distal retention region to have a spherical region, which in the expanded state of the occlusion device fits tightly to the internal walls of the atrial appendage in the atrial appendage to be occluded and forms a force-fit connection with internal walls of the atrial appendage, so holding the implanted and expanded occlusion device in the atrial appendage, the proximal retention region of the occlusion device occluding the opening of the atrial appendage.
WO 02/071977 discloses Implant devices for filtering blood flowing through atrial appendage ostiums, which have elastic cover and anchoring substructures. Filter elements in the covers block emboli from escaping through the ostiums. Devices with tine substructures may have H-shaped cross sections, which devices seal the appendages by pinching an annular region of ostium tissue between the cover and the anchoring substructures. The shallow deployment depth of these H-shaped devices allows use of a universal device size for atrial appendages of varying lengths. The device may be made of braided elastic wire.
In other embodiments of WO 02/071977 a distinct proximal cover substructure 1120 is attached to a cylinder shaped wire braid device structure 1200. However, these devices lack flexibility due to the necessary attachment of the cover to the cylinder.
U.S. Pat. No. 6,168,622 discloses an aneurysm occlusion device that has a bulbous body portion and an anchor. The body portion is sized to be received within an aneurysm and the anchor is sized and shaped to engage an interior surface of the vessel's wall. The body portion and the anchor are integrally formed of a resilient fabric permitting the occlusion device to be collapsed for deployment and resiliently self-expanded to include the aneurysm. However, the devices disclosed in U.S. Pat. No. 6,168,622 are anchored in the aneurysm by having the bulbous body portion and the anchor larger than a central portion inbetween, wherein the central portion is approximately of the size of an opening or neck N of the aneurysm in the blood vessel wall tissue. The anchor of the aneurysm occlusion device is sized to engage the vessel wall outside the opening to the aneurysm, and the bulbous portion has approximately the same volume as the volume of the aneurysm so as to substantially fill the aneurysm and secure the bulbous portion, having a larger dimension than the neck, therein. The central portion is centered in the neck. The purpose of the device is to prevent the aneurysm to become larger by providing a filling material secured therein. Moreover, clamps hold both ends of a cut braid together, which clamps may protrude from the device, lead to undesired side effects, such as thromboembolic complications.
In addition, an aneurysm is substantially different from an atrial appendage and the aneurysm occlusion device is not suited for occluding an atrial appendage. For instance, the constantly beating heart muscle and demands for a different anchoring mechanism preventing dislodgement and migration of the device. Also, the ostium of the atrial appendage is not in all anatomical cases a neck portion, but rather an opening of substantially the same dimension than the cross section of the atrial appendage. Therefore the anchoring of the aneurysm occlusion device of U.S. Pat. No. 6,168,622 would not be sufficient to fulfill the requirements of an atrial appendage occlusion device.
Hence, there is a need for an improved atrial appendage occlusion device. Accordingly, an improved atrial appendage occlusion device would be advantageous and in particular an atrial appendage occlusion device allowing for increased flexibility, cost-effectiveness, patient friendliness and/or patient safety would be advantageous.